It sure is hard to chain down a good man to play the S&M demigod Christian Grey.

On Saturday, it was announced that British actor Charlie Hunnam was dropping out of the lead role in the “Fifty Shades of Grey” film adaptation.

Universal Pictures stated that “Hunnam’s immersive TV schedule” was to blame for “not allowing him to adequately prepare for the role of Christian Grey.”

But insiders say the 33-year-old “Sons of Anarchy” star was overwhelmed by the fanfare and fearful of being typecast — especially in such a raw and explicit movie.

It’s a difficult role to cast.

“Clearly [Grey] should be sexy but he shouldn’t be wearing his sexiness on his sleeve. There should be some depth to him,” says casting director Brooke Thomas. Her top choice? Christian Bale, who has a history of playing charming psychopaths with a resume that includes “American Psycho.”

Nearly 90,000 “Fifty Shades” fans have signed an online petition to get “White Collar” star Matt Bomer in the kinky role. He’s the 2-1 favorite.Photo: Robert Ascroft/USA Network

“Vampire Diaries” star Ian Somerhalder has the bite — and the intense eyes — to play the domineering tycoon. He’s ready for his breakout film role.Photo: Gregg DeGuire/WireImage

“He’s charming with a little deviance to him,” says casting agent Brooke Thomas on why Christian Bale is her top pick to play Grey.Photo: Ian Gavan/Getty Images

But with an Aug. 1, 2014, release date already cemented, and shooting to commence Nov. 5, they’ll take whomever they can get. Movie execs and “Fifty Shades of Grey” author E.L. James have been scrambling to find a replacement smoldering enough to play Grey, a helicopter-flying, bondage-loving business tycoon.

And someone with enough heat to sizzle alongside Dakota Johnson, the 24-year-old daughter of Melanie Griffith tapped as the female lead role of innocent Anastasia Steele. (Hunnam and Johnson’s on-camera chemistry supposedly sealed the deal for the male heartthrob.)

One strong contender to get it on with Johnson is openly gay actor Matt Bomer, whose fan base surpasses his name recognition.

European bookmaker Paddy Power says Bomer has 2-to-1 odds of snagging the role.

Bomer groupies have been campaigning for the “White Collar” star to put on the famed gray tie — racking up nearly 90,000 signatures on an online petition. “Matt Bomer is as close to what E.L. James describes in the book,” says Barbara Osorio, a super fan in Chile who launched the petition through change.org and goes by the handle @d0tezayn on Twitter. “He has the elegance, talent and boldness it takes to play Christian Grey.”

But one Hollywood source says Bomer’s not a viable option.

“Bomer is shooting [‘The Normal Heart’] right now, where he plays an AIDS patient, so he’s super-skinny and not really goodlooking,” says the source.

Some good-looking — and new — names being thrown around include “True Blood” star Alexander Skarsgard, 37, and Jamie Dornan, a 31-year-old Northern Irish actor who stars in BBC’s “The Fall.”

And previous contenders, like “Divergent” hottie Theo James, 28, “I Am Number Four” actor Alex Pettyfer, 23, and “Vampire Diaries” stud Ian Somerhalder, 34, are rumored to be back in the running. (Somerhalder’s rep had no comment.)

Robert Pattinson is said to be E.L. James’ top pick for the part.Photo: George Pimentel/WireImage

Dakota Johnson, the daughter of Melanie Griffith and Don Johnson, will play Anastasia Steele.Photo: Jon Kopaloff/FilmMagic

Paddy Power says Pettyfer has 3-to-1 odds, Somerhalder 4-to-1.

Despite all the hype and potential stardom that could come from playing Grey, it’s a role that could backfire. Die-hard fan Michele Yogel, 34, who was one of the first New York women to read the book, thinks the part is too risky for an A-list star: “I don’t know if a big-name actor could be taken seriously by the fans,” says Yogel. “You want someone who can blend into the role.”

Matthew Belloni, executive editor at the Hollywood Reporter, says the future Mr. Christian Grey will be someone who “needs a career boost” and “can benefit from a high-profile role.”

Plus, A-listers cost too much money, especially since execs want to keep the budget low in the $30 million range.

“When you start to talk about major movie stars, you start to talk about big salaries,” says Belloni.

One thing most of the current contenders have going for them is a willingness to undress in front of the camera. Dornan is a former Calvin Klein model (who has yet to make it big in the States), Skarsgard went full-frontal in “True Blood,” and Bomer and Pettyfer both gyrated like pros in the stripper flick “Magic Mike.”

Hollywood honchos are already stacking their favorites against each other now that Grey is up for grabs.

In addition to Bale, casting director Thomas says her “runners-up would be James Marsden, Ian Somerhalder and Alexander Skarsgard.” (According to Paddy Power, Marsden is not a strong contender.)

Ultimately, though, E.L. James has final say on who fills Grey’s shoes.

Belloni says the scribe is very involved in the casting process.

“I’m told she’s giving a sign-off on everyone,” he says.

On Saturday, after Universal released its official statement, James took to Twitter to send a perfunctory message Hunnam’s way. “I wish Charlie all the best,” she tweeted.

For now, James & Co. are buckling in for a bumpy ride to find Grey. As the British author tweeted over the weekend:

Ian Somerhalder gets my vote. Matt Bomer's face, body and physique are absolutely PERFECT to play the part IMHO - just what I would have envisioned, reading the books - and a much better choice, physically, than Charlie Hunnam would have been. But unfortunately, knowing that the REAL guy is gay would just ruin the movie for me.

Nope, I don't care if a person is gay, and I don't care if s/he is OPENLY gay. I just couldn't enjoy "Christian Grey" knowing the actor is *acting*, no matter how good he may be at it. Sorry, Mr. Bomer. No offense intended there.